This invention relates to a self cleaning screen for use with an air flow which is particularly but not exclusively designed for use with an engine cooling system.
Radiator type cooling systems of internal combustion engines used for example in an agricultural environment often require a screen upstream of the radiator so that air drawn through the radiator is filtered to extract dust and other particles in the air. In the agricultural environment the air drawn into the radiator carries dust, soil particles, plant materials such as chaff and other debris which must be separated to prevent clogging of the radiator with this material. Various proposals have previously been put forward for screen designs and it is of course essential that the screen be effectively self cleaning since the screen itself would otherwise become quickly clogged and valueless.
In order to reduce air flow velocity through the screen to enable easier cleaning of the screen, it is often desirable to have a large screen which is significantly larger than the air intake.
However, this causes difficulty in providing a necessary moving element which allows the portions of the screen to be cleaned on a regular basis.
It is one object of the present invention therefore, to provide an improved design of screen which enables the screen to be manufactured to any required shape while allowing that screen shape to be simply and readily cleaned.
According to the invention, therefore, there is provided a self cleaning screen for separating particles from an air stream comprising a housing defining a front surface which is covered by a filter screen having perforations sized to halt the particles while allowing the air stream to pass through, a rear surface spaced from the front surface and a surrounding side wall means extending between the front surface and the rear surface to cause all airflow exiting the rear surface to be drawn through the front surface and the screen, a plurality of divider plates each extending from a front edge of the plate at the screen in a rearward direction to a rear edge of the plate at said rear surface of the housing, said divider plates being spaced each from the next so as to divide the screen into plurality of separate screen elements, the air flow through the screen element being confined on respective sides by said divider plates, the rear surface of the housing having at least a portion thereof which is open to allow passage of the air through the screen and between the plates, and baffle means for halting flow of air through each one of said separate screen elements in turn to allow material collecting on said each element in turn to be discharged from the screen.
Preferably the housing includes a back plate which has an opening smaller than the screen. A portion of the baffle within the smaller opening can then cooperate with the divider plates which direct the air toward the opening to close off the separate air channels defined by the divider plates in turn.
This allows for example, a simple rotating vein type arrangement mounted in a circular opening in the back plate to control cleaning of a much larger screen of any desired shape for example, rectangular.
With the foregoing in view, and other advantages as will become apparent to those skilled in the art to which this invention relates as this specification proceeds, the invention is herein described by reference to the accompanying drawings forming a part hereof, which includes a description of the best mode known to the application and of the preferred typical embodiment of the principles of the present invention, in which: